Lexmoto xtrs 125cc engine/gearbox issues

[Dtm1990]

Hi,

I know the basics about bikes but I have a problem with my bike and cannot figure out the problem and was hoping someone here could help out..

I have a lexmoto xtrs125cc which I am the first owner it is just over a year old and up until about 2 weeks ago it was running fine.

Basically when I am riding my bike is fine until I get to 5th gear it will run fine for a mile or two, but then it will lose revs from about 10000 to 7000 then totally cuts out unless I close the choke and open and close the throttle rapidly when your doing 60mph down a busy road things get a bit hairy. Especially when my speed rapidly goes down also..

I have recently taken it to a garage to get them to clean and reset my carb as I thought that was the problem.

The mechanic said he had cleaned the carb and the pilot jet was slightly blocked which he has sorted out. But it has not fixed the problem.

Also when I get between 6000 and 10000 rpm my volt/battery meter flickers up to max and down to zero

Any way these two things are related?

Anyone have any ideas?

The bike has been serviced regularly. Had a new rear tyre and brake pads

[rider555]

I would check your electrics, clocks on them lexmoto are not very reliable so you can't judge by voltage meter what is happening, I know this because I had the same problem when I purchase my 2nd hand one, check all connectors/plugs, test voltage of battery when engine is off and when you idle then rev bike up, test regulator, you will need multimeter for that, on left hand side fairings where your indicator is there will be 2 plugs( 3 yellow wires and I think is green/blue white on the other plug) have a look at them, also have a look at the throttle cable, remove tank you will see that throttle cable splits in to 2 cables under tank, 1 cable go to top of carb the other goes to side for accelerator pump, when you twist throttle make sure the cable on accelerator pump end moves freely.

I don't trust any mechanics so I would remove carb my self and have a look, check needle make sure the clip holding needle is in middle notch and everything moves nice and smooth.

Start from basic them bikes are not complicated is just matter of checking things.

[TimR]

I agree could be simple start basic

Battery terminals being loose can cause loss of power at high rpm .

[Dtm1990]

Thanks for responses.

I have had the carb off myself and everything seems ok throttle cable isn't sticking on either cable where it splits

Battery terminals are nice and tight..

Could a problem with my electronics be affecting my revs and causing it to cut out while riding as both problems seem to happen in sync with each other voltmeter start flickering then 30-60 seconds later my revs go down and engine dies

Also today I noticed while riding if I don't go over 45 50 mph and run with half choke I have no problems with anything.

And when i start bike cold it struggles to idle till it is warm (which take a good 5 to 10 minutes ) then idles at about 4000 5000 rpm I have tried adjusting it but it goes from one extreme to another high revs when warn to not being idle just from turning idle screw slightly I mean just enough to see idle screw start turning.

I'm going to take all panels off my bike so it is just frame engine and wires and check all wires and connectors cleaning them as I check see if that helps. I don't have multimeter yet need to find someone who has one or wait till payday to buy one.

[rider555]

Thanks for responses.

I have had the carb off myself and everything seems ok throttle cable isn't sticking on either cable where it splits

Battery terminals are nice and tight..

Could a problem with my electronics be affecting my revs and causing it to cut out while riding as both problems seem to happen in sync with each other voltmeter start flickering then 30-60 seconds later my revs go down and engine dies

Also today I noticed while riding if I don't go over 45 50 mph and run with half choke I have no problems with anything.

And when i start bike cold it struggles to idle till it is warm (which take a good 5 to 10 minutes ) then idles at about 4000 5000 rpm I have tried adjusting it but it goes from one extreme to another high revs when warn to not being idle just from turning idle screw slightly I mean just enough to see idle screw start turning.

I'm going to take all panels off my bike so it is just frame engine and wires and check all wires and connectors cleaning them as I check see if that helps. I don't have multimeter yet need to find someone who has one or wait till payday to buy one.

 

to check electrics you will need multimeter, it well could be where the battery just doesn't have the juice to power the igintion ect. but then again you saying everything works fine when half choke on and not going faster then 50 mph I know from riding around you get a lot of vibration on them is well after 50 mph, have a look under tank for coil ignition, lead from spark plug to top of frame, will have black lead with spade connector and green lead under screw on frame make sure the nice and tight.

http://www.lexmoto.co.uk/part/INTC010.php

Where about are you might be able to pop over to give your a hand even if is just for testing electrics, send me PM

[TimR]

Either your carb is running extremely lean

Or you may have an air leak between carb and cylinder hence

[rider555]

TimR could be right, loosen tank off and support, get your self carb cleaner and when engine is running spray around intake and see if engine revs raise or drops or note of engine change that way you could easily indicated you have air leak.

[Dtm1990]

Rider555 I am near skegness lincolnshire

I will have to look at my bike on Monday as I'm working all day Sunday

Will keep you posted if I find anything that could be problem

[Dtm1990]

I stripped my bike checked all electrical connections by connecting them one at a time and my revs go up when I disconnect the regulator.

When I reconnected the regulator I disconnected everything one at a time and noticed revs increasing when.i disconnect headlights.

On checking cables for headlights they all seem perfect condition.

Am I right in thinking regulator is faulty if it is causing the electrical problem.

Coudlnt get carb cleaner to check for air leaks so I just put hand over the air box intake and couldn't hear or feel it sucking air from any where inbetween air box and engine so do t think there's an air leak.

May just buy a new regulator and carb from lexmoto.co.uk website or from cmpo as they come ready to just plug and play basically no setup needed.

[fastbob]

Lack of fuel due to a partially blocked internal fuel filter ?

[Dtm1990]

Could be totally ignored the fact that the fuel tank could have crap in it

On a side note I had to replace fuel and vacuum hoses as vacuum hose to fuel pump had a slight tear in it so I replaced both but still made no difference to any performance

[rider555]

I stripped my bike checked all electrical connections by connecting them one at a time and my revs go up when I disconnect the regulator.

When I reconnected the regulator I disconnected everything one at a time and noticed revs increasing when.i disconnect headlights.

On checking cables for headlights they all seem perfect condition.

Am I right in thinking regulator is faulty if it is causing the electrical problem.

Coudlnt get carb cleaner to check for air leaks so I just put hand over the air box intake and couldn't hear or feel it sucking air from any where inbetween air box and engine so do t think there's an air leak.

May just buy a new regulator and carb from lexmoto.co.uk website or from cmpo as they come ready to just plug and play basically no setup needed.

 

Don't buy stuff with out checking things first, unplugging regulator will rise revs, get your self a multimeter to check, you don't need expensive one. When you unplug lights revs will raise also as there is no load, on them lexmoto lights are run by regulator recifier if you have pink wire coming out of regulator

Video below shows how to test regulator, you should get same sort of reading touching green wire on 1 plug and each yellow wire on the other, something in region of 0.480, mine recent was .267, .387,.485 my reg was faulty

">

If I'm right once you block of your air intake, revs should drop if there is no change then you have air leak.

I don't think your problem is electrics but worth a look with out spending money on parts.

[Dtm1990]

Having my hand over intake the engine slowed until it cut out ao dont think theres an air leak.

Also when I removed the regulator and reconnected my voltmeter on dash is not flickering up and down anymore may just ride it for a week or so and see if it has sorted it out the volt meter now sits at 9 volts in stead of up and down

I'm gonna have to get a multimeter.

Regulator is in 30 quid

http://www.lexmoto.co.uk/part/REGR055.php?model=KS125-24

Carb is also only 30 quid

http://www.lexmoto.co.uk/part/CRB059.php

[eastanglianbiker]

if you have no can of carb cleaner wd40 will show you if its leaking air anywhere as well

[rider555]

Having my hand over intake the engine slowed until it cut out ao dont think theres an air leak.

Also when I removed the regulator and reconnected my voltmeter on dash is not flickering up and down anymore may just ride it for a week or so and see if it has sorted it out the volt meter now sits at 9 volts in stead of up and down

I'm gonna have to get a multimeter.

Regulator is in 30 quid

http://www.lexmoto.co.uk/part/REGR055.php?model=KS125-24

Carb is also only 30 quid

http://www.lexmoto.co.uk/part/CRB059.php

 

if your volt meter sits at 9v is definitely something wrong with electrics that is if your meter is working correctly, bike idle should sits beetween 12-15 and when you rev bike needle should get to 15.

Multimeter at Halfords for £7.99 would let you test the stator/regulator and battery with out any problem

http://www.halfords.com/workshop-tools/tools/hand-tools/rolson-digital-multimeter

[Wynne G Oldman]

Next time it happens, pull over and undo your petrol cap. If there's a sucking sound as air goes into the tank, it's either a blocked breather hole in the petrol cap, or a blocked breather pipe.

[Dtm1990]

Sorry late reply

I rode my bike without regulator connected and it still has a problem with electronics.

Also I have 4 days off next week and will keep adjusting my carb until it gets better if it does not I will get an new carb

Another thing I can't remember if I mentioned is that a few weeks before I was getting the fuel problems was that my bike would backfire a few times when riding but that has now stopped.

[rider555]

Sorry late reply

I rode my bike without regulator connected and it still has a problem with electronics.

Also I have 4 days off next week and will keep adjusting my carb until it gets better if it does not I will get an new carb

Another thing I can't remember if I mentioned is that a few weeks before I was getting the fuel problems was that my bike would backfire a few times when riding but that has now stopped.

 

You can't ride with out regulator connected, it controls charging circuit, so no wonder you still have problem with electrics, you know what you need to check so unplugging things wont help

[megawatt]

How many miles has it done. The carb doesn't normally wear out, why buy a new one?

[Dtm1990]

I only rode it for about 10 miles to see if it was causing the problem..

Also it's done 10000km since February this year

[megawatt]

Most carbs have replaceable components. Rarely do you need a new carb.

[rider555]

I only rode it for about 10 miles to see if it was causing the problem..

Also it's done 10000km since February this year

 

Unplugging "faulty" regulator won't show up anything, you only draining your battery riding with out plugged in, you might have other problem somewhere else but you need to check few things over, 10k since Feb that bike of yours deserves good service and looking after, getting new carb at this moment is no point, and I tell you now adjusting that carb is not fun at all when is on bike, you can barely get screw driver on to idle screw never mind on fuel/air mixture screw which is just in front of carb above starter motor.

If you decide to strip that carb you want to make sure needle clip is in middle, air fuel mix screw on mine is best at 2 and 1/2 turn out from close, I fitted new main jet 100 as the std one that was fitted was 94.5 to small for that bike.